Arc lamp



(No Model.) 3 Sheets-Sheet 1.

T. E. ADAMS. ARC, LAMP. N0. 380,074. Patented Mar. 27, 1888.

W e .e. y

I 1 law N. PETER5.-Phclo4.imogmphcn Washington D. C.

(No Mbdel.) 3 Sheets-Sheet 2. T. E. ADAMS.

v ARC LAMP.

- No. 380,074. Patented Mar. 27,1888.

I a. ummlmmm W I.

g JUNE??? v (No Model.) 3 Sheets-Sheet 3.

- T. E. ADAMS.

AR MP UNITED STATES PATENT OFFICE.

THOMAS ADAMS, OF CLEVELAND, OHIO.

ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 380,074, dated March 27, 1888.

Application filed July 11, 1887. Serial No. 243,991. (No model.)

To all whom it may concern:

Be it known that I, THOMAS E. ADAMS, of Cleveland, in the county of Ouyahoga and State of Ohio, have invented certain new and useful Improvements in Are Lamps; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make .and use the same.

In arc lamps as ordinarily constructed the arrangement is such that upon an abnormal decrease of current, or when the current entirely ceases, the feeding carbon will freely slip through theclutch and will fall down upon the stationary carbon, striking the same with some force, and if the two carbons happen to be out of alignment, which frequently occurs, the carbons will overlap, so that upon the re-es-' tablishment of the arc the same'will be formed, not between the ends proper of the carbons,but in a great measure between the sides of the same. As a consequence of this the arc is not always visible from all sides in a horizontal plane passing through the same, and the intercepting bodies of the carbons cast heavy shadows into the field of vision. If the carbons thus overlap, they frequently bind against each other with such force that the arc-establishing mechanism is too weak to separate them, and at other times the overlap is so great that the carbons still remain in contact after one of them has been raised by the arc establishing mechanism.

Another objection to are lamps as ordinarily constructed is found in the fact that when the cut-out is frequently operated the contacts become oxidized by the sparks which there occur as often as contact is made or broken. In consequence thereof the resistance at the contacts soon becomes abnormally great and the contacts become heated by the passage of a current of normal strength. This in turn causes a still further increase of resistance and continued oxidation. Besides this, the intimacy of contact at the cut-out is always more or less imperfect, .by reason of the fact that the contact-surfaces are presented to each other in a definite invariable manner, while the surfaces themselves vary considerably under the effects of usage, and more especially by reason of incipient fusion caused by the sparks.

The solenoids or electro-magnets necessarily employed in arc lamps disclose other defects of the same. The cores of the solenoids should move centrally within the same in order to act to the best advantage; but it is found in practice that they are generally biased to one side or the other, and, unless specially provided against, prompt and delicate action would be impaired. These solenoids also become more or less heated by the action of the current and there are no provisions for cooling the same effectively, and the dash-pots, especially when air is used as a resisting medium, are ordinaril y so arranged that dust will accumulate within the same and will obstruct their easy and smooth action.

It is the primary object of my invention to overcome the difficulties and vexations resulting from the defects which I have thus briefly indicated, and the main features of my invention are designed to accomplish this object in a simple and effective manner. In addition thereto, however, my invention also comprises certain details of construction designed to improve the arc lamp generally, and with a view to this secondary object the structural elements are shaped and located relative to each other to insure freedom and ease of movement of the parts and to protect them against injury or obstruction from detached particles of the contact-brushes and from the heating effect of'the current.

In the preferred form of my arc lamp I avoid the use of all springs for actuating the moving parts, so that the frequent adjustment necessitated by changes of the normal tensions of such springs is entirely avoided; and in modified forms of my arc lamp I make use of a single spring only, the function of which is so simple and emphatic that a change of tension of the same cannot seriously affect the operation.

All this will more fully appear from the following detailed description, in which reference is made to the accompanying drawings, which form a part thereof, and in which- Figure 1 is an elevation, partly in section, of the preferred form of my improved arc lamp; Figs. 2 and 3, like views of modified forms of the same; Fig. 4, a perspective view of my improved cut-out; Fig. 5, a vertical section of the movable contact of the cut-out; Fig. 6, a plan view of my improved clutch; Fig. 7, a vertical section through a solenoid provided with my arrangement for ventilating the same; Fig. 8, a vertical section through a ventilated solenoid provided with my improved dash-pot, and Fig. 9 an elevation of a double-arc lamp constructed in accordance with my invention.

The general arrangement of my improved single-are lamp is indicated in Fig. 1.

B and C are arc-establishing and feed-regulating solenoids, as is usual in lamps of this character. The former is of low resistance, while the resistance of the latter is considerable, as is well understood by those skilled in the art. The cores B C of these solenoids are pivotally connected to a lever, L, which has its fulcrum in a stud, L, upon the lower head of solenoid G, or in any other fixed part of the lamp. Core 0 is thus connected to the short arm and B to the long arm of lever L; but this inequality is partly compensated by a weight, X, formed with or attached to the end of the shorter arm.

H is a clutch which receives the carbonholding rod R, and it is connected at one end with lever L bythe lifting-rod O, and is at the other end in operative relation to the combined trip and stop A Projecting from lever L near its fulcrum is a short stud, Q, and a con tact-block, E, mounted in said stud in a peculiar man ner,is adapted to make and break contact with two fixed contactblocks, 1 and 2, when the lever swings one way or the other. The three blocks 1, E, and 2, constitute the cut-out, as will be hereinafter more fully explained.

S is a contact-brush which carries the main current to the carbon-ho1ding rod R.

M M are the carbons, and I the resistance coil in the circuit of the cut-out.

Theparts so far described are in the main common in are lamps, and the operation of such lamps is well understood. The current from the positive pole of the generator, entering at P,is led to solenoid B by a suitable eonductor. It leaves this solenoid by a wire, \V, which connects with contact-brush S. The current then proceeds to carbon-holder R, to the carbons M and M, (supposing these to be in contact,) and by a conductor, N, to line or back to the negative pole of the generator. A branch current also passes by wire P through the high-resistance coil 0, which latter is included in a constantly-closed shunt around the are and another branch circuit by wire W, cut-out 1, E, and 2, and resistance-coil I; but the current through solenoid B will preponderate and core B will be lifted, actuating lever L, which in turn will raise carbon M by means of clutch H, and will at the same time open the cut-out. The are being thus established, the length of the same will be regulated by the dili'erential action of the solenoids or electro-magncts B and G, as is well understood.

In lamps constructed as thus far indicated the clutch II abuts with its free end against a fixed stop, so that it clamps the carbon-carrier It when it is raised by the lifting-rod O and releases the same when by the descent of core B it is returned to its original position. Thus, when the resistance of the arc becomes abnormally great, or when the current entirely fails, the upper carbon freely descends by its own weight-,aided by that of the carbon-holder,aml forcibly strikes the lower carbon, and if not in perfect alignment with the same it overlaps the latter, as hereinbefore described. This de feet in the operation of arc lamps I overcome in the following manner: I provide an electro magnet, A, of low resistance in the circuit of solenoid B in advance of the latter, so that the current from P first traverses the coil of this electro-magnet before it reaches the solenoid. From a point, D, between the eleetromagnet A and solenoid B the branch to the cut-out 1, E, and 2 and resistance I proceeds, so that electro-magnet A is always in circuit, either with solenoid B or with the cut-out, or with both. The armature A of the electromagnet A, pivoted at A, carries at its free end the combined trip and stop A for the clutch H. This stop is U-shaped, and the free end H of the clutch, entering the prongs of the stop, has free motion between the same.

By reference to Fig. 6 it will be seen that the shape of clutch H somewhat approaches that of a distorted lozenge, with the opening H for the reception of the carbon-carrier R much nearer to the point I-P, where the lifting-rod O connects, than to the free end H. At and about opening H the body of the clutch is necessarily enlarged; but by reason of the greater length of the part extending from H to H the clutch, if pivotally supported at H will have adecided tendency to drop down with its free end. Such pivotal support is afforded bylifting-rod O, which is reduced at its upper end, and which with its reduced portion 0' enters the hole H and is bent to the shape of a hook, as is clearly shown in Fig. 1. Thus hooked to the lifting-rod, the clutch rests by its own weight upon a knife-edge, 0', formed at thejunction ot' the hook O with the body of the lifting-rod. The hole H is countersunk to afford free play to hook O, and it will be understood that this construction reduces the friction between the clutch and lifting-rod to a minimum.

The weight of cores or armatu res B and G and the lengths and weights of the two arms of lever L are so adjusted that B preponderates and is in its lowest position, while 0 is at its highest position, when there is no current through the lamp. This condition isillustrated in Fig. 1, and it will be understood thatclutch H is also in its lowest position, with its free end overhanging and the edges of opening H binding against carbon-holder It. The latter is therefore clamped when there is no current through the lamp. In this respect my lamp dififers radically from other are lamps which feed by gravity. The clamping of the feeding carbon is enhanced by the weight of armature A, the free end of which armature rests with the upper prong of the U-shaped stop A upon the free end of the clutch. In this condition the movable contact E of the cut-out bridges and presses against the stationary contacts 1 and 2. The cut-out is therefore closed. If, now, current is turned on, it will pass from P to and through electro-rnagnet A, leaving the same at D. At this point the current divides, one portion passing through the solenoid B and by wire W, brush S, carbon-holder, and carbons out by conductor N, while the other portion will pass by wire W, the cut out, and resistance I, as above described. Another branch will pass through the constantlyclosed shunt I O, as is well understood.

The current through solenoid B is not sufficient to raise core B enough to actuate the next instant, the cut-out being now open, the

whole current will pass through solenoid B, (excepting the portion which passes through the constant shunt,) and core B will now be actuated sufficiently to lift the end of clutch H through the intermediary of lever L and lifting-rod O. The clutch by the tendency of its free end to descend will bind upon the carbon-holder,' and the continued upward movement of core B, lever L, and clutch H will raise the carbon M and establish the arc. The movement of the armature A is followed by that of lever L so rapidly that the two movements may be considered as taking place simultaneously; but there is, in fact, a release of the carbon-h older by the action of armature A preceding the clamping and effective lifting of the same by the action of lever L, whereby the feeding carbon is allowed to rest for a very short time by its full weight upon the lower carbon before it is actually separated from the latter. The rapid succession of the sudden release of the upper carbon by the action of armature A and the equally sudden clamping of the same by the action of lever L is of advantage, in that it insures good contact between the carbons immediately before the establishment of the arc. The are being once established, the lamp will be regulated by the differential action of the two solenoids B and O in a manner well understood by those skilled in the art.

If it should happen that the carbons are not in contact when the current is turned on, there will be a circuit through the lamp by way of electro magnet A and the cut-out. This .current will energize magnet A, which, attracting its armature A, will cause the latter to lift the free end of the clutch and release the carthe current is diverted into the shunt P O.

Solenoid G will then overbalance solenoid B, core 0 will rise, lever L will be lifted by its short arm, and the cut-out will be closed. This will divert almost the whole current from solenoid B and the are, and, the latter disappearing, the lamp will be cut out.

If the lamp burns an arc of normal length and the current is suddenly turned off, armature A drops away from its magnet and allows the free end of clutch H to tip down. This clamps the carbon-holder instantly, and the same is now carried down by the clutch actuated by lever L in consequence of the downward movement of core B. This downward movement is limited to the extent ofthe length of the arc, which is proportional to the elevation of core B. Thus the upper carbon will just come in contact with the lower carbon, but will not pass the same if the two should not be in perfect alignment. This downward movement of the feeding carbon is a positive movement in the sense that it takes place with and is controlled and limited in eX- tent by the downward movement ofthe core B.

If the arc should become abnormally long and the current be turned off while the lamp is in this condition, the downward movement of the carbonholdcr will ordinarily not be sufficient to establish contact between the carbons; but if nowthe current is turned on again the lamp will automatically relight in the manner above described.

From the foregoing description it will now be understood that the function of the clutch as constructed and mounted in my improved are lamp is to clamp the carbon-holder and stop downward motion of the same when there -is no current or only a weak current through reference to Fig. 1as, for instance, by the mechanismshown in Fig. 2. In this case there is a retractile spring, J,which keeps the armature A away from its magnet, and at the same time pulls upon a hooked rod, J, the hook of which tilts the clutch H to bind against and prevent downward motion of the carbonholder B. When by the passage of a current electro-magnet A is energized, hooked rod J is lowered and ceases to control the clutch, which is now under the control of lever L and gravity-claw L, as will be readily understood.

It will be seen in Fig. 2 that the claw L is pivoted to lever L and loosely embraces the clutch, and that it is guided in its upanddown movement by a recess cut into the baseplate of the lamp, so that it will always engage the clutch. If at any time after the establisment of the arc the current is cut off, the retractile spring J will draw up the hooked rod J, which will tilt the clutch-ring and clamp the carbon-holder, while the core of the solenoid l3, lever L, &c., will move down, leaving the carbons out of contact. In this respect the modified lamp shown in Fig. 2 differs from the lamp shown in Fig. 1. In Fig. 3 the same kind of operation takes placethat is to say, upon cessation of the current, the feeding carbon will remain suspended, while the mechanism of the lamp will descend; but in this case there are two clutches to perform the functions of the clutch H in Figs. 1 and 2. The auxiliary clutch J .is caused to clamp the carbon-holder when there is no current by spring J, and releases the same when magnet A is energized, while clutch H, which is under the control of the solenoids, as in Fig. 2, establishes the arc and regulates the feed. The ring'clutch J is pivoted in a forked hanger, J and rests with one edge upon one end of the armature-lever A, which, as in Fig. 2, is pivoted in the middle at X.

IVhile no springs are employed in the feeding and stop motion mechanism shown in Fig. 1, which is the preferable construction, there is, as has been seen, a retractile spring in the modified constructions shown in Figs. 2 and 3; but it will be observed that these springs are not of a delicate nature and the unavoidable changes of tension of these springs cannot materially affect the operation of the lamp. Besides this,these springs may be readily omitted if the armatures are made heavy enough so as to lift hooked rod J and clutch H in Fig. 2 and clutch J in Fig. 3. In all these forms the fundamental idea is embodied that an abnormal decrease of current or the cessation of current, which without my improvement would operate to release the carbon holder, shall cause the clamping of the latter, so as to prevent its free and unimpeded sudden descent by gravity. While this is accomplished by my improvement, it also serves another beneiicial purpose.

Sometimes, by reason of an ill-fitted or damaged part of the lamp, the carbon-holder will stick in its bearings and will not feed down with ease, as it should. In such cases the arc will soon become abnormally long and will be cut out by the preponderating action of solenoid G. This, however, as has been explained above, will leave electro-magnet A in the circuit of the cut-out, and armature A, remaining in its attracted position, will continue to hold the clutch II free of the carbon rod, so that should a jar release the red the same can descend by gravity and establish contact between the two carbons, whereupon the lamp will automatically relight. To prevent this accident as much as possible, the rod is made round and smooth and without any interior mechanism. The clutch H is placed above the contact-brush in my preferred form of lamp, so that detached bristles or wires from the brush cannot lodge within the clutch and bind the rod, and the top of the bushing U, through which the rod passes, is reduced to an edge, so that small portions of wire, fee, will be deflected from the same.

The cut-out is constructed with special reference to are lamps, although it will find application in other electrical apparatus where frequent breaks of circuit occur, which, when a powerful current is used, is apt to spoil the contactsurfaees by the action of the sparks. There are two vertical posts, 1 and 2, secured to the base-plate or other fixed part of the lamp, but insulated from the same, as will presently appear. Screws 3 pass loosely through the base-plate and screw one into each post, and washers 5 and 6, of asbestus or other flexible, insulating, and refractory material, are placed one on each side of the base-plate between the latterand the post and between the base-plate and a metallic washer, 4, respectively. The screw-head is forced against the metal washer, and the latter, being conical or rounded on the side toward the base'plate, forces washer 5 into and through the hole in the base-plate through which screw 3 passes. This hole is made much wider than is neces sary for the screw to pass through it. It is shaped conical or rounded on the side toward washer 5, and the latter is forced through the same into contact with asbestus washer 6,so that the screw is completely surrounded by asbestus, as by a thimble. This mode of securing two metallic structures to each other, so as to be and remain insulated from each other under the heating effect of the currents or sparks, I deem of specialgimportance; but, since this part of my invention has a wide range of application in all kinds of electrical apparatus, I make no broad claim to the same in this application. I, however, reserve my right to make an independent application for this in vention. Each post 1 and 2 has one vertical side shaped ilat, and the two posts are so mounted as to have the flat side of one at an obtuse angle to that of the other, as will be seen by reference to Fig. 4. The contact-block E is mounted upon stud Q, projecting from lever L, by aball-andsocket joint, as illustrated in Fig. 5. The general shape of block E is that of an ellipse. It is composed of a metal core, V, in which the socket for the ball V, constituting the head of a screw which screws into stud Q, is formed. This core is surrounded by an insulating-sleeve, V, of mica, asbestus, or other refractory material, and this in turn by a metal sleeve, V, which is designed to ICC make contact with blocks 1 and 2. One side of sleeve V is extended beyond the body of block E at E and to the inner side of this extension is secured a spring, E, having its free ends bent around the edge of extension E so as to be in advance of the outer surface of sleeve V If, now, by the operation of lever L contact-block E is forced toward posts 1 and 2, the free ends of spring E will make contact with the said posts first, and, being forced back by the continued movement of block E, sleeve V will come into contact with the flat sides of posts 1 and 2. If a spark should occur upon the establishment of the contact, it will pass between the lowermost portions of posts 1 and 2 and the ends of spring E, but will not pass between V and the corresponding surfaces of posts 1 and 2, so that these parts will not be oxidized by the action of the current and will always present good metallic contact-surfaces. The same thing will happen when the contact is broken, as in that case the ends of spring E are the last to leave posts 1 and 2, as will be readily understood. Spring E thus furnishes a pair of elastic auxiliary contacts which operateto divert the sparks produced by breaking or making contact from the contact-surfaces proper. This spring may therefore properly be called a spark-catcher.

If it should happen that the ends of the spring be fused by the sparks and stick to the lower portions of the contactsurfaces of blocks '1 and 2, or to one of them, the spring will be torn away when the movable block E breaks contact without being bent out of its proper shape. This accident, however, is easily avoided by lining the ends of the spring with platinum.

Block E, being mounted so that it may turn about its vertical axis, will adapt itself to the surfaces of the contact-blocks 1 and 2 under all circumstances, so that good electrical contact will always be insured in the cut-out, and, since the contact-surfaces are all in vertical planes, dust and other insulating impurities cannot easily settle upon the same. It will be readily understood that in place of one spring secured to. a movable block of the cutout I may use two springs, one secured to each stationary block, as spark-catchers, as indicated in dotted lines in Fig. 4.

In Figs. 7 and 8 my improved ventilated solenoid, with dust-proof dash-pot, is illustrated. The sleeve 7, which receives the core 8, is at the upper end screw-threaded internally, and a screw-threaded plug, 9, closes this end of the solenoid-sleeve. An axial hole through the plug is cylindrical and screwthreaded at its upper part and expands into a dome-shaped cavity, from which an opening, 11, communicates with the external air. This opening registers with a similar opening in a collar, 12, placed over sleeve 7 between the head of the plug and the flange of the solenoid, and is secured by a screw, 13, or otherwise, as shown. A screw, 14, engaging the threads in the cylindrical portion of the cen- 'tral hole in the plug, clamps the solenoid to its support 15. The core of the solenoid is necessarily of such diameter as to move w1th ease within the sleeve, and there is, therefore, always a free space between the core and the inner wall of the sleeve, through which air may enter from below, and, being heated by contact with the sleeve and core, may pass out by opening 11. I have found that this air-passage operates effectively to cool the soleno d, which otherwise becomes sometimes quite hot under the action of the current.

In order to moderate the violence of the action of the core of the solenoid, I employ a dash-pot, as is usual; but in order to prevent the settling of dust Within the same I so inclose it within the core of the solenoid that it is practically free from dust and other obstructions. An inverted bell, 16, cylindrical in form, is loosely hung to the end of screw 14 by a hook and eye, 17, or otherwise, and a piston, 18, which is well fitted to the bore of the bell, is similarly connected to a plug, 19, by a connecting-rod, 20. Said plug is screwthreaded and closes the lower end of the hollow core 8; but one or more holes, 21, either in the wall of the core or in plug 19, or in both, admit air into the hollow core and into the lower part of bell 16, whereby additional means for ventilation and cooling are afforded. The piston 18 may be solid or hollow, and in the latter case it should be placed within the bell with its open end toward the closed end of the bell, as shown.

The operation of a dash-pot is so well understood that a special description of the same seems unnecessary; but it will be easily seen that in an air dash-pot inclosed within the core of the solenoid, as above described, no dust or other obstructions can reach the actuating parts of the same, so as to clog the piston or to render its functions uncertain. It will also be understood that a solenoid constructed substantially as described can be easily taken apart for inspection and repairs.

In solenoids it frequently happens that the magnetic axes of the coil and core do not coincide with the mathematical axis of the bore of the solenoid, and in such cases when current is passed through the coil the core assumes, or tends to assume, a position at an angle with the axis of the bore and to bind against the same. In arc lamps in which no provision is made against this occurrence this is a great disadvantage, and often prevents the true and unobstructed operation of the same. I overcome this difficulty by placing a balancing magnetic shield, consisting of an iron or other magnetic plate, 13 or C of suitable dimensions, about the solenoid in such position as to produce coincidence between the magnetic and mathematical axes. The

part of the solenoid to which the iron plate is to be fastened is easily found by turning the plate from place to place until a position is reached where the core of the solenoid moves IIO without binding. The proper adjustment may also be obtained by placing the iron plate farther from or nearer to the solenoid, as by the interposition of some indifferent packing; or the plate, once applied, may be filed oil, 850. Instead of applying the balancing magnetic shield to the exterior of the solenoid, the same may be inserted within the solenoid, either on the outer or on the inner side of sleeve 7; but the construction shown is preferable on ac count of the ease with which it may be applied.

I have so far described my invention with reference to an arc lamp in which a single arc is maintained; but it is clear that all my improvementsare equally applicable todoubleare lamps. All that is required to so apply my improvements is to use two sets of earbons, two brushes electrically connected, two clutches, each operated by a separate lifting rod connected with the operatinglever, two U-shaped clutch-trips branching from the armature of the stop-motion magnet, and a balance-wire for the first rod to rest upon when down.

In Fig. 9such double-arc lamp is illustrated with the duplicated parts marked with the same letters of reference, and the construction is so simple and the operation so identical with that of a single-arc lamp that no particular description is deemed necessary. It will, however, be observed that in this case, in place of solenoid Oand its movable core, I have shown a two-legged electro-magnet with its armature G placed between the projecting pole-pieces C. This is an obvious modification which is sometimes preferred, but which does not atfeet the principle of operation. If such magnet is used in place of a solenoid, the armature is made beveled and plays between the beveled ends of the pole-pieces. This avoids all possibility of binding and enables me to adjust the length of the normal are by adj usting either the pole-pieces nearer to the armature or the armature nearer to the pole-pieces.

In Fig. 9 I have indicated a means for the former adjustment. It consists of a screw, 22, passing through the pole-pieces, and by turning said screw to the right or left the cores may be adjusted nearer to each other and to the armature or farther away.

In my construction of are lamps the feeding carbon is held by the clutch when there is no current through the lamp. It is therefore desirable to lift the free end of the clutch when a new carbon is inserted or when it becomes otherwise necessary to push the carbon-h older up. For this purpose I provide a rod, A, loosely hung to the U -shaped trip A and passing through a hole in the base-plate.

\Vhether a solenoid or an electro-magnet be employed in the constantly-closed shunt-circuit, it is always desirable to have the resistance as great as possible; but it is found that if the resistance is furnished by the coils of copper wire of the solenoid or electro-magnet exclusively the force of such magnet or solenoid will be greater than necessary, and, in

fact, greater than desirable. For this reason, in order to obtain a solenoid having the desired lifting-power and as great a resistance as may be obtained, Iuse onlyso much copper wire as is necessary to obtain that liftingpower and then add as many convolutions of German-silver wire as are necessary to obtain the desired resistance. The coils of German silver wire are preferably placed over the coils of copper wire, so that the heat generated in the high-resistance medium may be carried off into the air.

I do not claim in this application the construction shown in Fig. 3 specifically, but intend to claim the same in a separate application.

Having now fully described my invention, I desire to emphasize the fact that I do not propose to limit myself to the details of construction herein shown and described, except so far as they are specifically defined in the subjoined claims.

I claim 1. In an arc lamp, the combination, with a gravity-feeding carbon and a clutch adapted to normally clamp and support the same when no current traverses the lamp, of two electromagnets or solenoids,one for actuating the clutch and releasing the carbon to the action of gravity and the other to actuate the clutch to clamp and raise the carbon and establish the are, substantially as described.

2. In an arc lamp, the combination, with a gravity feeding carbon and a clutch constructed to normally clamp and support the feeding carbon when no current traverses the lamp, of an electromagnet for raising one side of the clutch and releasingits grip on the carbon, and an electro-magnet or solenoid for raising the opposite side of the clutch and clamping and raisingthe carbon,snbstantially as described.

3. In an arc lamp, the combination, with a gravity-feeding carbon and a clutch adapted to normally clamp and support the same when no current traverses the lamp, of an electromagnet or solenoid in the main circuit and a movable support connected therewith for supporting one side of the clutch while the carbon is normally clamped and for elevating the same side of the clutch to clamp and raise the carbon, and another electro-magnet and armature combined therewith for raising the opposite side of the clutch to release the carbon from the same and to allow it to feed, substantially as described.

at. In an arc lamp feeding by gravity, the combination, with the carbon-holder of the feeding carbon and a clutch constructed and adapted to normally clamp and support the same when no current traverses the lamp, of a solenoid or equivalent magnet in the main circuit, a cut-out operated by said solenoid, and an electro-magnet in the circuit of the are and cut-out and adapted to lift the clutch and release the carbon when an effective current traverses the lamp, substantially as set forth.

IIC)

5. In an arc lamp feeding by gravity, the combination, with the carbon-holder of the feeding carbon and a pivoted gravity-clutch constructed to normally clamp and support the same when no current traverses the lamp, of a solenoid or equivalent magnet in the main circuit, a cutout operated by said solenoid, and an electro-magnet in the circuit of the arc and cut-out and adapted to lift the clutch and release the carbon when said magnet is energized, substantially as set forth.

6. In an arc lamp feeding by gravity, the combination of a gravity-clutch arranged to normally clamp the feeding carbon when no current traverses the lamp, with an electromagnet in the circuit of the are for disengaging the clutch from the carbon-holder and a solenoid for engaging the same for establishing the arc, substantially as described.

7. In an arc lamp, the combination, with a gravity-feeding carbon and an electro-magnet or solenoid in the main circuit, and an electromagnet or solenoid in the shunt-circuit for establishing and regulating the arc, of agravityclutch for normally clamping and supporting the feeding carbon when no current traverses the lamp, and a supplemental electromagnet in the main circuit having an armature connected with the clutch for actuating it to release the carbon to the action of gravity, substantially as described.

8. In an arc lamp feeding by gravity, the combination of a pivoted-gravity-clutch which normally clamps the feeding-carbon holder with an electro-magnet in the circuit of the arc, an armature for said magnet, and a trip for the clutch engaging the latter in both directions, carried by the armature, whereby the clutch clamps the carbon-holder when no current traverses the carbons and tends to release it when current passes through the same, substantially as described.

9. In an arc lamp feeding by gravity, the

combination, with the feeding carbon, a gravity-clutch constructed and adapted to normally clamp the feeding carbon and support it out of contact with the non-feeding carbon when no current is passing through the lamp, and a cut-out adapted to diverta portion of the current from the main magnet of'the regulator, of an electroinagnet in the circuit of the cutout and provided with an armature constructed to engage the free end of the clutch and disengage it from the feeding-carbon holder and allow the latter to descend by gravity, substantially as set forth.

10. In an electric-arc lam p,the combination, with a gravity-feeding carbon and a gravityclutch constructed to normally clamp and support the carbon-holder when no current traverses the lamp, of an electro-magnet in the main circuit for actuating one side of the clutch and releasing it from thecarbonholder, and a solenoid in the main circuit and a solenoid in the shunt-circuit for operating differentially upon the other side of the clutch and actuating it to establish the arc, regulate the length of the arc, and the feed of the carbon, substantially as described.

11. In an are electric lamp, the combination, with a gravity-feeding carbon and a gravityclutch constructed to normally clamp and sup port the carbon-holder of the feeding carbon when no current traverses the lamp, of differential magnets for actuating one side of the clutch and asupplemental magnetin the main circuit for actuating the other side of the clutch,

substantially as described.

12. In an arc electriclamp, the combination, with a gravity-feeding carbon and a gravityclutch constructed to normally clamp and support the carbon-holder when no current traverses the lamp, of the feeding carbon'of two solenoids, one in the main circuit and the other in a shunt circuit, and a support connected therewith and actuated thereby for supporting and moving one side of the clutch, and asupplemental magnet in the main circuit provided with an armature constructed to actuate the other side of the clutch and to limit its upward-and-downward movement,

'at one end and normally clamping the feeding carbon holder, two solenoids in the main and in a shunt circuit, respectively, acting differentially upon the clutch to establish and regulate the arc, and a cutout controlled by the solenoids, with an electro-magnet in the cutout circuit acting upon the overbalancing end of the clutch to clamp and release the carbon,

substantially as described.

15. In an arc lamp feeding by gravity, a gravity ring-clutch having a countersunk hole at one end, in combination withahooked lifting-rod engaging the hole in the clutch with its book and having aknife-edge formed upon its body to support the clutch, substantially as described.

16. In an arc lamp feeding by gravity, a lozenge-shaped ring-clutch having the ring formed nearer to one end than the other, in

combination with a knife-edged lifting-rod supporting the clutch at the end nearer the ring, substantially as described.

17. In an electric-lamp cut-out, the combination, with two stationary contact-blocks having practically vertical contact'surfaces, of a movable contact-block connected to a rocking bar or lever by a ball-.and-socket joint, so

that it may have both a lateral and an oscillating movement, and thereby engages an extended vertical and lateral surface on each of IIO the stationary contact-blocks, substantially as described.

18. In a cut-out included in an electric circult, the combination, with two stationary contact-blocks having practically vertical contact-surfaces, of a self-adjustable movable c011- tact-blocl adapted to bridge and make contact with the vertical contact-surfaces of the two stationary contacts, the movable contact being constructed with an extended contact-surface having openings at its opposite ends, and a spring secured behind the normal contact-surface and having its ends arranged to project forwardly through the openings at the opposite ends thereot', substantially as set forth.

19. In a solenoid, the combination of a core which loosely fits the bore of the solenoid, so as to leave an air-passage between the core and the sleeve, with a separate air-passage between the space of the bore above the core and the external atmosphere, substantially as described.

20. A solenoid having air-passages con1municating with the external atmosphere at both ends of the bore, substantially as described.

21. In a solenoid, the combination of a sleeve over which the coils of the solenoid are wound, with a plug closing one end of the sleeve and having an air-passage connecting the interior of the sleeve with the external air and a loosely-fitting core entering the other end of the sleeve, substantially as described.

22. The combination, with a solenoid and a hollow core, of a bell or cylinder having a closed upper end pivotally or loosely connected at its upper end to the solenoid and a piston fitting into the bell or cylinder, the piston-rod being pivotally or loosely connected at its lower end to the core of the solenoid, substan- 0 tially as set forth. 1

23. The combination,with a solenoid having a hollow core, of a plug for closing the upper end of the bore of the solenoid, a dash-pot bell suspended from said plug and extending Wlblllil the core, a plug for closing the lower end oi the core, and a piston for the bell connected with the core-plug, substantially as described.

24. A combined solenoid and dash-pot consisting, essentially, of a sleeve for the coils of the solenoid, a plug closing one end of the sleeve, a hollow core loosely fitting into the sleeve and also plugged at one end, the operating parts of the dash-pot loosely connected with the plugs and extending within the core,

and air-passages through the plugs, substan- 1 tiall y as described.

25. The combination, with a solenoid and its core, of a magnetic balance for producing coincidence between the magnetic and mathematical axes of the solenoid and its core, substantially as described.

26. The combination, with a solenoid and its movable core, of a magnetic plate applied to the solenoid to neutralize the lateral bias of the core, substantially as described.

27. The combination, with a solenoid and its movable core, of an iron plate attached to the exterior of the coils to counterbalance the lateral bias of the core, substantially as described.

In testimouy whereof I have signed this specification in the presence of two subscribing witnesses.

THOMAS E. ADAMS.

\Vitnesses:

G. W. PATTERSON, J. SVGRIBBEN. 

